Many businesses have dedicated communications systems that enable computers, servers, printers, facsimile machines and the like to communicate with each other, through a private network, and with remote locations via a telecommunications service provider. In, for example, commercial office buildings, the dedicated communications system may be hardwired using communications cables that contain conductive wire. In such hard wired systems, modular wall jacks such as RJ-45 style jacks are mounted in offices throughout the building. Communications cables are run through, for example, the walls and/or ceiling of the building to electrically connect each jack to network equipment (e.g., network routers and servers) that are located in, for example, a computer room. Communications cables from external telecommunication service providers may also terminate within the computer room.
Communications patching systems may be used to connect the communications cables running from the modular wall jacks in offices throughout the building to the network equipment in the computer room. These communications patching systems may facilitate terminating the cables in an organized fashion, and may also simplify the process for later making changes to the connections between communications cables. Typically, a communications patching system includes one or more equipment racks. Network equipment such as, for example, network servers and switches may be mounted on these racks, as may one or more “patch panels.” As is known to those of skill in the art, a “patch panel” refers to an interconnect device that includes a plurality of jacks such as, for example, RJ-45 style jacks, on at least one side thereof. Each jack is configured to receive a mating plug of a patch cord (i.e., a communications cable with a modular plug on at least one end thereof). Communications cables may also be terminated into the back end of some or all of the jacks in the patch panel (the communications wires of each cable are typically terminated into individual contacts on the back end of the jack such as, for example, insulation displacement contacts). Thus, each jack of the patch panel may provide a communications paths between a patch cord that is plugged into the jack and a communications cables that is terminated into the reverse side of the jack. The connectivity between the individual wall jacks and the ports on the network equipment can be modified by simply rearranging the connectivity of the patch cords that are plugged into the patch panels.
FIG. 1 is a simplified example of one way in which a computer 12 in an office 10 of a building may be connected to network equipment 62, 66 located in, for example, a computer room 30 of the building. As shown in FIG. 1, the computer 12 is connected by a patch cord 14 to a modular RJ-45 style wall jack 20 that is mounted in a wall plate 16 in office 10. A communications cable 22 is routed from the back end of the modular wall jack 20 through, for example, the walls and/or ceiling of the building, to the computer room 30. As there will often be hundreds or thousands of wall jacks 20 within an office building, a large number of cables 22 are routed into the computer room 30. As is known to those of skill in the art, in twisted pair communications systems, such as the system depicted in FIG. 1, each of the communications cables, patch cords and jacks, such as cables 22, patch cord 14 and jack 20 of FIG. 2, will typically include eight conductive paths which are arranged as four pairs of conductive paths. Each of these pairs of conductive paths may be used to transmit a differential signal. Thus, the communications channel that is formed by a cascade of jacks, cables and patch cords that connects a first piece of equipment (e.g., computer 12 in FIG. 1) to a second piece of equipment (e.g., network router 66 of FIG. 1) may carry a total of four different communications signals over the four differential pairs of conductive paths.
A first equipment rack 40 is provided within the computer room 30. A plurality of patch panels 42 are mounted on the first equipment rack 40. Each patch panel 42 includes a plurality of jacks 44. In FIG. 1, each jack 44 comprises an RJ-45 style jack that is configured to receive an RJ-45 style plug. As shown in FIG. 1, each communications cable 22 that provides connectivity between the computer room 30 and the various offices 10 in the building is terminated onto the back end of one of the jacks 44 of one of the patch panels 42 on equipment rack 40. A second equipment rack 50 is also provided in the computer room 30. A plurality of patch panels 52 that include jacks 54 are mounted on the second equipment rack 50. A first set of patch cords 46 (only two exemplary patch cords 46 are illustrated in FIG. 1) are used to interconnect connector ports 44 on the patch panels 42 to respective ones of the connector ports 54 on the patch panels 52. The first and second equipment racks 40, 50 may be located in close proximity to each other (e.g., side-by-side) to simplify the routing of the patch cords 46.
As is further shown in FIG. 1, network equipment such as, for example, one or more switches 62 and network routers and/or routers 66 are mounted on a third equipment rack 60. Each of the switches 62 may include a plurality of jacks 64. A second set of patch cords 56 connect the jacks 64 on the switches 62 to the back end of respective ones of the jacks 54 on the patch panels 52. Note that, in the example of FIG. 1, the first end of the patch cord 56 is directly terminated into the back of one of the jacks 54, while the second end of patch cord 56 includes a plug connector. As is also shown in FIG. 1, a third set of patch cords 70 may be used to interconnect other of the jacks 64 on the switches 62 with jacks 68 that are provided on the network routers 66. In order to simplify FIG. 1, only a single patch cord 56 and a single patch cord 70 are shown. Finally, one or more external communications lines 72 are connected to, for example, one or more of the network routers 66 (either directly or through one or more patching devices).
The communications patching system of FIG. 1 may be used to connect each computer, printer, facsimile machine and the like 12 located throughout the building to local area network (“LAN”) switches 62. The LAN switches 62 are connected to the network routers 66, and the network routers 66 are connected to external communications lines 72, thereby establishing the physical connectivity required to give devices 12 access to both local and wide area networks. In the patching system of FIG. 1, connectivity changes are typically made by rearranging the patch cords 46 that interconnect the jacks 44 on the patch panels 42 with respective of the jacks 54 on the patch panels 52.
The equipment configuration shown in FIG. 1, in which each wall jack 20 is connected to the network equipment 62, 66 through at least two patch panels 42, 52, is referred to as a “cross-connect” patching system. In another commonly used equipment configuration, which is typically referred to as an “inter-connect” patching system, the communications path from each modular wall jack 20 to the network equipment 62, 66 typically passes through a single patch panel (e.g., equipment rack 40 is omitted from the system of FIG. 1, and the cables 22 are connected into the reverse side of the patch panels 52). In such interconnect systems, patching changes are made by rearranging the patch cords 56 that run between the patch panels 52 and the network switches 62.
Electronic equipment such as, for example, the computers, switches and routers servers depicted in FIG. 1 above can be susceptible to electronic static discharge (“ESD”). ESD occurs when a static charge accumulates on a first object and the first object comes in close proximity or contact with a second object, thereby allowing the charge to suddenly transfer to the second object. In some instances the charge can be very large such as, for example, on the order of several thousand volts. Unfortunately, charges of this magnitude can cause catastrophic damage to many types of electronic equipment.
In hardwired telecommunications systems such as the exemplary system depicted in FIG. 1, the horizontal cabling (cables 22 in FIG. 1) and/or the patch cords (e.g., patch cords 46, 56 in FIG. 1) can become charged. If a cable 22 becomes charged, then when the patch cords 46, 56 are fully connected (i.e., when the first end of patch cord 46 is inserted into a jack 44 on one of the patch panels 42, the second end of patch cord 46 is inserted into a jack 54 on one of the patch panels 52 and the end of patch cord 56 that includes a plug is inserted into a jack 64 on one of the switches 62), then the charge can be transferred from the cable 22, through the patch cord 46, through the patch cord 56 to the switch 62 where the charge is discharged. Similarly, if either of the patch cords 46 or 56 become charged before they are plugged in, the charge on the patch cord can be transferred to the switch 62 when the patch cords 46 and/or 56 are inserted in their corresponding jacks. In either case, the switch 62 can be damaged by the electronic static discharge of the charge that was present on the cable 22 or one of the patch cords 46, 56. If the patch cord 70 that connects the switch 62 to the router 66 becomes charged before it is connected, it can discharge into either the switch 62 or the router 66 when the patch cord 70 is connected (it would discharge into the piece of equipment into which the patch cord 70 was first connected). In all of these situations, the electronic static discharge can damage or even destroy the effected piece of equipment (i.e., switch 62 or router 66).
In order to prevent such damage, patch panels and/or switches may include a grounded jack (typically on a side surface). The contact wires of this grounded jack are each coupled to ground. Before installing a patch cord into a normal jack of such a patch panel or switch, the installing technician is supposed to first plug the patch cord into the grounded jack to discharge any built up static charge to ground. Then the technician would plug the other end of the patch cord into the normal jack on the patch panel to discharge any static charge on the cable attached to the normal panel jack. The patch cord may then be plugged into the normal jack without the risk of ESD damage. Additionally, jacks are also known which include grounding circuits that automatically ground a patch cord as it is being inserted into the jack. An example of such a jack is disclosed in U.S. Pat. No. 7,431,600.